Laboratory Evaluation of Steinernematid Nematodes Against Grasshoppers, 1992

Abstract

Abstract Laboratory tests were conducted to determine the effectiveness of a commercial preparation of steinernematid nematodes, BioSafe, on 5 species of grasshoppers. The nematode suspension was prepared according to label directions. Clipped barley (2 wk old) was spread out on toweling and sprayed with the nematode suspension. Three microscope slides were placed on the toweling at regular intervals to determine the concentration of nematodes sprayed. A small hand sprayer was used for application. The number of nematodes was counted in each of 5 randomly selected microscope fields on each slide. The concentration of nematodes sprayed averaged 2.9 ± 0.34 per mm2. After spraying, the barley was divided equally and placed in clear plastic containers (10 cm diam, 6 cm high) with screened tops. Twelve adult grasshoppers of each species were placed in each container. The test was replicated twice. As a check, untreated barley was placed in one container for each species. The containers were checked daily for 20 d and dead grasshoppers were removed and stored at 4°C for later dissection. Cumulative percent mortality was calculated for each container. Dead grasshoppers were dissected to confirm the presence of nematodes in grasshoppers from treated containers.